The present invention relates to a method for producing a golf club head, more particularly to a method for producing a hollow golf club head having an opening capable of reducing the mass of the golf club head and improving the durability of a junctional portion between a metallic head main body and a cover for the opening made of a low specific gravity material.
In order to lower the center of gravity of a wood-type hollow golf club head, there has been proposed a head (a) which is, as shown in FIG. 6(a), composed of a head main body (c) made of a metal material and provided with a crown opening (b), and a crown cover (d) covering the crown opening (b) and made of a material having a lower specific gravity than that of the head main body. The head main body (c) is provided with a supporting part (f) for supporting a peripheral edge part (e) of the crown cover (d). The head main body (c) is produced by a lost-wax casting method from a viewpoint of the production efficiency.
In the lost-wax casting method, however, as shown in FIG. 6(b) which is a cross sectional view taken along line D-D of FIG. 6(a), in order to make it easy to remove the core (not shown) used to form a wax model, an internal corner (h) between the supporting part (f) and the inner surface (c1) of the head main body (c) has to be rounded, and thereby the round portion is increased in the thickness.
Thus, in the case of the head main body (c) produced by such lost wax casting method, the mass of the golf club head is increased due to the increased thickness, and the design freedom of the center of gravity of the head is decreased.
Further, between the peripheral edge part (e) and the supporting part (f), a region having a higher rigidity is formed due to the increased thickness, therefore, cracks are liable to occur in the junctional portion between the head main body (c) and the crown cover (d), and the durability of the golf club head in particular the crown portion is deteriorated.